From c8b30da7ef48edb3d43e07d2c1b8622d8123c3a9 Mon Sep 17 00:00:00 2001
From: Ben Taylor <btaylor@openjdk.org>
Date: Thu, 4 Dec 2025 22:11:48 +0000
Subject: [PATCH] 8373039: Remove Incorrect Asserts in shenandoahScanRemembered

Reviewed-by: wkemper, ysr, xpeng
---
 .../gc/shenandoah/shenandoahScanRemembered.cpp   | 16 +++-------------
 1 file changed, 3 insertions(+), 13 deletions(-)

diff --git a/src/hotspot/share/gc/shenandoah/shenandoahScanRemembered.cpp b/src/hotspot/share/gc/shenandoah/shenandoahScanRemembered.cpp
index 44064dbd1a9..a3c96a7d53b 100644
--- a/src/hotspot/share/gc/shenandoah/shenandoahScanRemembered.cpp
+++ b/src/hotspot/share/gc/shenandoah/shenandoahScanRemembered.cpp
@@ -335,7 +335,6 @@ HeapWord* ShenandoahCardCluster::first_object_start(const size_t card_index, con
     if (ctx->is_marked(p)) {
       oop obj = cast_to_oop(p);
       assert(oopDesc::is_oop(obj), "Should be an object");
-      assert(Klass::is_valid(obj->klass()), "Not a valid klass ptr");
       assert(p + obj->size() > left, "This object should span start of card");
       assert(p < right, "Result must precede right");
       return p;
@@ -362,15 +361,15 @@ HeapWord* ShenandoahCardCluster::first_object_start(const size_t card_index, con
 
   // Recall that we already dealt with the co-initial object case above
   assert(p < left, "obj should start before left");
-  // While it is safe to ask an object its size in the loop that
-  // follows, the (ifdef'd out) loop should never be needed.
+  // While it is safe to ask an object its size in the block that
+  // follows, the (ifdef'd out) block should never be needed.
   // 1. we ask this question only for regions in the old generation, and those
   //    that are not humongous regions
   // 2. there is no direct allocation ever by mutators in old generation
   //    regions walked by this code. Only GC will ever allocate in old regions,
   //    and then too only during promotion/evacuation phases. Thus there is no danger
   //    of races between reading from and writing to the object start array,
-  //    or of asking partially initialized objects their size (in the loop below).
+  //    or of asking partially initialized objects their size (in the ifdef below).
   //    Furthermore, humongous regions (and their dirty cards) are never processed
   //    by this code.
   // 3. only GC asks this question during phases when it is not concurrently
@@ -382,15 +381,6 @@ HeapWord* ShenandoahCardCluster::first_object_start(const size_t card_index, con
 #ifdef ASSERT
   oop obj = cast_to_oop(p);
   assert(oopDesc::is_oop(obj), "Should be an object");
-  while (p + obj->size() < left) {
-    p += obj->size();
-    obj = cast_to_oop(p);
-    assert(oopDesc::is_oop(obj), "Should be an object");
-    assert(Klass::is_valid(obj->klass()), "Not a valid klass ptr");
-    // Check assumptions in previous block comment if this assert fires
-    fatal("Should never need forward walk in block start");
-  }
-  assert(p <= left, "p should start at or before left end of card");
   assert(p + obj->size() > left, "obj should end after left end of card");
 #endif // ASSERT
   return p;